Remove unnecessary `buildPhase`.

flake.nix

@@ -25,10 +25,6 @@
             src = ./.;
             version = "0.1.3";
             nativeBuildInputs = with pkgs; [ cmake ];
-            buildPhase = ''
-              cmake -DCMAKE_BUILD_TYPE=Release .
-              cmake --build .
-            '';
             installPhase = ''
               mkdir -p $out/bin
               cp ./bootstrap $out/bin

specs/clang/template/CMakeLists.txt

@@ -1,6 +1,13 @@
 cmake_minimum_required(VERSION 3.15)
 project("<NAME>" VERSION 0.1.0)
 
+# The default CMAKE_BUILD_TYPE is undefined, i.e. toolchain specific. Enforcing
+# a default makes builds work more consistently.
+if (NOT CMAKE_BUILD_TYPE)
+  message("CMAKE_BUILD_TYPE was not set. Defaulting to Debug")
+  set(CMAKE_BUILD_TYPE Debug)
+endif()
+
 # The primary executable.
 add_executable("<NAME>" main.c)